DRAM Bender: An Extensible and Versatile FPGA-based Infrastructure to Easily Test State-of-the-art DRAM Chips

To understand and improve DRAM performance, reliability, security and energy efficiency, prior works study characteristics of commodity DRAM chips. Unfortunately, state-of-the-art open source infrastructures capable of conducting such studies are obsolete, poorly supported, or difficult to use, or their inflexibility limit the types of studies they can conduct. We propose DRAM Bender, a new FPGA-based infrastructure that enables experimental studies on state-of-the-art DRAM chips. DRAM Bender offers three key features at the same time. First, DRAM Bender enables directly interfacing with a DRAM chip through its low-level interface. This allows users to issue DRAM commands in arbitrary order and with finer-grained time intervals compared to other open source infrastructures. Second, DRAM Bender exposes easy-to-use C++ and Python programming interfaces, allowing users to quickly and easily develop different types of DRAM experiments. Third, DRAM Bender is easily extensible. The modular design of DRAM Bender allows extending it to (i) support existing and emerging DRAM interfaces, and (ii) run on new commercial or custom FPGA boards with little effort. To demonstrate that DRAM Bender is a versatile infrastructure, we conduct three case studies, two of which lead to new observations about the DRAM RowHammer vulnerability. In particular, we show that data patterns supported by DRAM Bender uncovers a larger set of bit-flips on a victim row compared to the data patterns commonly used by prior work. We demonstrate the extensibility of DRAM Bender by implementing it on five different FPGAs with DDR4 and DDR3 support. DRAM Bender is freely and openly available at https://github.com/CMU-SAFARI/DRAM-Bender.Comment: To appear in TCAD 202

TuRaN: True Random Number Generation Using Supply Voltage Underscaling in SRAMs

Prior works propose SRAM-based TRNGs that extract entropy from SRAM arrays. SRAM arrays are widely used in a majority of specialized or general-purpose chips that perform the computation to store data inside the chip. Thus, SRAM-based TRNGs present a low-cost alternative to dedicated hardware TRNGs. However, existing SRAM-based TRNGs suffer from 1) low TRNG throughput, 2) high energy consumption, 3) high TRNG latency, and 4) the inability to generate true random numbers continuously, which limits the application space of SRAM-based TRNGs. Our goal in this paper is to design an SRAM-based TRNG that overcomes these four key limitations and thus, extends the application space of SRAM-based TRNGs. To this end, we propose TuRaN, a new high-throughput, energy-efficient, and low-latency SRAM-based TRNG that can sustain continuous operation. TuRaN leverages the key observation that accessing SRAM cells results in random access failures when the supply voltage is reduced below the manufacturer-recommended supply voltage. TuRaN generates random numbers at high throughput by repeatedly accessing SRAM cells with reduced supply voltage and post-processing the resulting random faults using the SHA-256 hash function. To demonstrate the feasibility of TuRaN, we conduct SPICE simulations on different process nodes and analyze the potential of access failure for use as an entropy source. We verify and support our simulation results by conducting real-world experiments on two commercial off-the-shelf FPGA boards. We evaluate the quality of the random numbers generated by TuRaN using the widely-adopted NIST standard randomness tests and observe that TuRaN passes all tests. TuRaN generates true random numbers with (i) an average (maximum) throughput of 1.6Gbps (1.812Gbps), (ii) 0.11nJ/bit energy consumption, and (iii) 278.46us latency

Assessment of Serotonin Metabolite 5-hydroxyindoleacetic Acid Levels in Urine Sample for Diagnosis and Treatment Efficacy in Children with Dysfunctional Voiding and Their Interaction with Biofeedback Therapy

Objective:Dysfunctional voiding (DV), which is explained as an incoordination between the external urethral sphincter and the bladder, is a situation developing in neurologically normal children. Serotonin has some effects on the lower urinary tract which cannot be fully explained. The selective 5-hydroxyindoleacetic acid (5-HIAA) agonist improves voiding efficacy in the rat model with voiding dysfunction as serotonin. Serotonin decomposes to 5-HIAA which excreted from urine. We considered that a problem in neuromodulator levels can lead to DV and evaluated the levels of 5-HIAA in urine.Materials and Methods:Our study included 130 children aged 5-15 years who were diagnosed with DV and 48 children with no urological complaints as controls. Urine samples were taken only once in control group, and 3 times [before and after the biofeedback treatment (sixth month and twelfth month)] in the study group to determine the difference and the interaction between 5-HIAA and biofeedback therapy.Results:Biofeedback therapy was found to be an effective method in the treatment of DV. However, there was no significant difference in the level of mean urine 5-HIAA/creatinine (u5-HIAA/Cr) between study (6.139±3.652) and control groups (6.374±4.329) (p=0.751). The mean u5-HIAA/Cr levels in the DV group at baseline and at the end of biofeedback therapy (6th month) were 6.249±4.132 and 6.19±4.715, respectively (p=0.951). The mean u5-HIAA/Cr levels in the DV group at baseline and at 12 months were 5.901±3.291 and 6.644±4.206, respectively (p=0.557). There was no significant difference in u5-HIAA/Cr levels between pre-treatment and post-treatment in the DV group.Conclusion:We still do not know if a problem at the level of neurotransmitter metabolite in the central nervous system plays a role in the etiology of DV. We evaluated this relationship, but we could not find a significant result. New studies are needed to get more information about the role of neuromodulators in the etiology and treatment of DV

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Abstract Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

Retroperitoneal Liposarcoma: Case Report

The most common type of soft tissue sarcomas is liposarcomas. It consists of 0.1-0.2% of all malignant tumors in adulthood. Retroperitoneal liposarcomas are generally seen in individuals between 40-60 years old, however are also seen in younger ages. MRI provides important information about localization of mass, tumor infiltration and relationship between vascular structures before the operation. In addition, CT and MRI provide reliable data about early diagnosis of local recurrence at follow-up. Aggressive surgical resection is the treatment option for extending survival. Nephroureterectomy should be added to aggressive resection. Due to high rates of local recurrence, patients should be followed-up by CT and MRI in first two years quarterly, then once in every 6 months per following 3 years. Here, we presented a case as follow; 50 years old male who complained with left flank pain and diagnosed as dedifferentiated liposarcomas